This is fairly close to how find already works in Firefox and Safari... instant, progressive advance-to-next-match and highlighting of all matches. I would expect that style to gradually migrate to other apps without any promotional effort.
Besides the fact that the keys/gestures for 'next/prev' and 'repeat' are a little different, what part of HandyFind isn't matched in these browsers?
My biggest complaint with current search in all the browsers is that if you don't find what you're looking for, it takes a while to realize what has happened since there is no obvious feedback (though FF is pretty good). Also, it isn't obvious if you have wrapped around or it is hard to find the text if the font is small.
If I were you, and I knew C well enough, I'd actually fix the search in Firefox or Chrome to implement these features, then use that to demonstrate my skill to clients, employers or fellow geeks.
I agree that's really nice... but what happens when the text isn't found? The feedback is that the page brightens. Even if I know to shift my eyes to the entry field, it feels odd to me that the feedback for something going wrong is that the page lightens up.
Besides the fact that the keys/gestures for 'next/prev' and 'repeat' are a little different, what part of HandyFind isn't matched in these browsers?